A large expansion ratio high-efficiency axial turbine

Abstract

The present application relates to the technical field of axial flow turbine, especially to a large expansion ratio high-efficiency axial flow turbine, which comprises a turbine hub and turbine blades, the turbine blade inlet tip wheel diameter is, the turbine blade outlet tip wheel diameter is, the turbine blade top axial chord length is, the relationship among the turbine blade inlet tip wheel diameter, the turbine blade outlet tip wheel diameter and the turbine blade top axial chord length is = 0~0.364, in this way, the traditional long blade pull wire design is abandoned, the blade height is limited, the blade root section is increased to reduce the root stress, the blade tip section area is greatly reduced, the intermediate section area is slightly smaller to improve the flow capacity, the wedge angle is optimized, the shock loss is reduced, the efficiency is improved, and the technical problem of the prior art that the turbine is designed as a long blade, the long blade needs to adopt a pull wire to ensure the strength, but the pull wire structure reduces the turbine flow area, thereby reducing the turbine efficiency and increasing the assembly difficulty of the axial flow turbine is solved.

Description

Technical Field

[0001] This invention relates to the field of axial flow turbine technology, and more particularly to a high-efficiency axial flow turbine with a large expansion ratio. Background Technology

[0002] As the power of marine diesel engines increases, there is a growing demand for higher pressure ratios in the turbochargers that are matched with them. As a key component, the expansion ratio of the turbine will also increase accordingly. On the other hand, with the introduction of the "carbon peaking and carbon neutrality" strategy, it is necessary to further improve the efficiency of turbochargers in order to reduce fuel consumption and improve emissions to meet increasingly stringent environmental standards.

[0003] Traditional turbines are mostly designed with long blades. Long blades require the use of reinforcing wires to ensure strength, but the reinforcing wire structure reduces the turbine's flow area, thereby reducing the turbine's efficiency and increasing the assembly difficulty of axial turbines. Summary of the Invention

[0004] The purpose of this invention is to provide a high-efficiency axial flow turbine with a large expansion ratio, which aims to solve the technical problem that existing turbines are mostly designed with long blades. Long blades need to use tie wires to ensure strength, but the tie wire structure will reduce the turbine flow area, thereby reducing the turbine efficiency and increasing the assembly difficulty of the axial flow turbine.

[0005] To achieve the above objectives, this invention employs a high-expansion-ratio, high-efficiency axial-flow turbine, comprising a turbine hub and turbine blades. The turbine blades are torsion blades, and there are multiple turbine blades evenly distributed along the axial centerline of the turbine hub. The inlet diameter of the turbine hub is [missing information]. The outlet diameter of the turbine hub is The axial chord length at the turbine hub is The relationship between the inlet diameter of the turbine hub, the outlet diameter of the turbine hub, and the axial chord length at the turbine hub is as follows: =0~0.364, the turbine blade inlet tip diameter is The turbine blade outlet tip diameter is The axial chord length at the tip of the turbine blade is The relationship between the turbine blade inlet tip diameter, the turbine blade outlet tip diameter, and the axial chord length at the turbine blade tip is as follows: =0~0.364.

[0006] Wherein, the aspect ratio of the turbine blades =1.6~1.65, the turbine blades with a high aspect ratio are beneficial to improving efficiency.

[0007] Wherein, the turbine blade outlet tip diameter =170~180mm.

[0008] Among them, the meridional expansion angle of the high expansion ratio high-efficiency axial flow turbine <20° <20°, and <30°.

[0009] Wherein, the turbine blade inlet airflow angle ≤75°, the turbine blade outlet airflow angle ≤70°.

[0010] Wherein, the turbine blade installation angle =10°~60°, leading edge wedge angle =10~21°, tail edge wedge angle =3~15°.

[0011] Among them, the maximum thickness of the turbine blade airfoil Distribution location =0.2~0.5; the leading and trailing edges of the blades are both ellipses with a length-to-diameter ratio of 1, and the thickness of the trailing edge of the turbine blade is ≥0.5mm.

[0012] This invention discloses a high-expansion-ratio high-efficiency axial flow turbine. This turbine abandons the traditional long-blade, wire-stretcher design, which limits blade height. Instead, it increases the blade root cross-section to reduce root stress, significantly reduces the blade tip cross-sectional area, and minimizes the intermediate cross-sectional area to improve flow capacity. It also optimizes the wedge angle, reduces shock wave loss, and improves efficiency. This invention solves the technical problem in existing technologies where turbines are often designed with long blades, requiring wire-stretchers to ensure strength. However, the wire-stretcher structure reduces the turbine's flow area, thus lowering efficiency and increasing assembly difficulty. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the high expansion ratio high efficiency axial flow turbine of the present invention.

[0015] Figure 2 This is a meridional view of the high expansion ratio, high efficiency axial flow turbine of the present invention.

[0016] Figure 3 This is a schematic diagram of the design parameters for the high expansion ratio high efficiency axial flow turbine of the present invention.

[0017] Figure 4 This is a schematic diagram of the wedge angle of the high expansion ratio high efficiency axial flow turbine of the present invention.

[0018] Figure 5 This is a schematic diagram of the turbine blade structure of the high expansion ratio high efficiency axial flow turbine of the present invention.

[0019] Figure 6 This is a view of the blade root of the turbine blade of the present invention.

[0020] Figure 7 This is a view of the blade of the turbine blade of the present invention.

[0021] Figure 8 This is a view of the tip of the turbine blade of the present invention.

[0022] 1-Turbine hub, 2-Turbine blade. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. Furthermore, in the description of the present invention, "a plurality of" means two or more, unless otherwise expressly specified.

[0024] Please see Figures 1 to 8 , Figure 1 This is a schematic diagram of the high expansion ratio, high efficiency axial flow turbine of the present invention. Figure 2 This is a meridional view of the high expansion ratio high-efficiency axial flow turbine of the present invention. Figure 3 This is a schematic diagram of the design parameters for the high expansion ratio, high efficiency axial flow turbine of this invention. Figure 4 This is a schematic diagram of the high expansion ratio, high efficiency axial flow turbine wedge angle of the present invention. Figure 5 This is a schematic diagram of the turbine blade structure of the high expansion ratio high efficiency axial flow turbine of the present invention. Figure 6 This is a view of the blade root of the turbine blade of the present invention. Figure 7 This is a view of the turbine blade of the present invention. Figure 8 This is a view of the blade tip of the turbine blade of the present invention. The present invention provides a high-expansion-ratio, high-efficiency axial flow turbine, including a turbine hub 1 and turbine blades 2. The turbine blades 2 are torsion blades, and there are multiple turbine blades 2. The multiple turbine blades 2 are evenly distributed along the axial centerline of the turbine hub 1. The inlet diameter of the turbine hub 1 is [missing information]. The outlet diameter of the turbine hub 1 is The axial chord length at the turbine hub 1 is The relationship between the inlet diameter of the turbine hub 1, the outlet diameter of the turbine hub 1, and the axial chord length at the turbine hub 1 is as follows: =0~0.364, the inlet tip diameter of the turbine blade 2 is The outlet tip diameter of the turbine blade 2 is The axial chord length at the tip of the turbine blade 2 is The relationship between the inlet tip diameter of the turbine blade 2, the outlet tip diameter of the turbine blade 2, and the axial chord length at the tip of the turbine blade 2 is as follows: =0~0.364;

[0025] In this embodiment, the high expansion ratio high-efficiency axial flow turbine abandons the traditional long blade tie wire design, which limits the blade height. Instead, the blade root cross-section is increased to reduce root stress, the blade tip cross-sectional area is significantly reduced, and the middle cross-sectional area is slightly reduced to improve flow capacity. The wedge angle is optimized to reduce shock wave loss and improve efficiency. This solves the technical problem in the prior art where turbines are mostly designed with long blades, which require tie wires to ensure strength. However, the tie wire structure reduces the turbine flow area, thereby reducing turbine efficiency and increasing the assembly difficulty of axial flow turbines.

[0026] Furthermore, the aspect ratio of the turbine blade 2 =1.6~1.65, the high aspect ratio of the turbine blade 2 is beneficial to improving efficiency.

[0027] In this embodiment, the axial chord length of the turbine blade 2 The axial dimensions of the meridional channel are determined by the axial chord length; a smaller axial chord length allows for a shorter axial length of the turbine under the same conditions. Considering vibration limitations, the aspect ratio should be optimized. A blade with an aspect ratio ≤ 5.5 is advantageous for improving efficiency; the turbine blade 2 of the present invention has an aspect ratio of ≤ 5.5. =1.6~1.65.

[0028] Furthermore, the outlet tip diameter of the turbine blade 2 =170~180mm.

[0029] In this embodiment, the maximum outer diameter of the turbine Due to the limitations of the overall engine structure size, it is generally required to use a smaller diameter while ensuring turbine performance in order to reduce material consumption, turbine mass, and cost. Therefore, the maximum outer diameter of the high expansion ratio high-efficiency axial flow turbine described in this invention is limited. =170~180mm.

[0030] Furthermore, the meridional expansion angle of the high expansion ratio high-efficiency axial turbine <20° <20°, and <30°.

[0031] In this embodiment, the meridional channel expansion angle , It can be used to control airflow parameters in the flow channel, but an inappropriate expansion angle can lead to flow losses. To avoid excessive flow losses, the meridional flow channel expansion angle of the high expansion ratio high-efficiency axial turbine is... <20° <20°, and <30°, the preferred meridional expansion angle of the high expansion ratio high-efficiency axial turbine in this invention is [missing value]. =0~3°, =5~10°.

[0032] Furthermore, the inlet airflow angle of the turbine blade 2 ≤75°, the outlet airflow angle of the turbine blade 2 ≤70°.

[0033] In this embodiment, the turbine blade 2 of the present invention is a twisted blade with different inlet and outlet airflow angles at the root, middle and top. The inlet angle of the blade increases with the increase of blade height. The maximum value of the rotor outlet airflow angle is 64.77°. From the blade root to the blade tip, the airflow turning angles are 52°, 89° and 100.9°, respectively. The work capacity is lowest at the blade root and highest at the blade tip.

[0034] Furthermore, the installation angle of the turbine blade 2 =10°~60°, leading edge wedge angle =10~21°, tail edge wedge angle =3~15°.

[0035] In this embodiment, the change in the blade profile installation angle of the turbine blade 2 directly affects the shape of the blade profile flow channel and the inlet and outlet angles. In this invention, the installation angle of the turbine blade 2 gradually increases from the blade root to the blade tip. As the installation angle increases, the blade thickness decreases. =15~18°, blade installation angle =42~45°, blade tip installation angle =47~50°;

[0036] The leading edge wedge angle of the turbine blade 2 It affects the maximum thickness of the blade cascade, the area of ​​the blade cascade, and the weight of the blade; it also affects the curvature of the pressure surface and suction surface profiles, and the leading edge wedge angle of the turbine blade 2. =18~21°, leading edge wedge angle of the leaf =12~15°, leaf tip leading edge wedge angle =16~19°;

[0037] The trailing edge wedge angle of the turbine blade 2 The thickness of the blade at the trailing edge and the magnitude of the trailing edge turning angle affect the expansion and acceleration of the airflow at the trailing edge, thus influencing the trailing edge wedge angle at the root of the turbine blade 2. =3~5°, mid-tail edge wedge angle =5~6°, leaf tip wedge angle, =10~12°.

[0038] Furthermore, the maximum thickness of the turbine blade 2-blade profile Distribution location =0.2~0.5; the leading and trailing edges of the blades are both ellipses with a length-to-diameter ratio of 1, and the trailing edge thickness of the turbine blade 2 is ≥0.5mm.

[0039] In this embodiment, the maximum thickness of the blade is... This is the maximum value among the inscribed circles of the blade profile. Currently, it is kept as small as possible while meeting requirements for structure, strength, cooling, and manufacturing. In the turbine blade 2 of this invention, to ensure strength, the blade root cross-section is increased to reduce root stress. To increase turbine flow capacity, the blade tip cross-sectional area is significantly reduced, while the middle cross-sectional area is slightly reduced. Therefore, the maximum thickness of the blade profile gradually decreases from the blade root to the blade tip, with the maximum thickness at the blade root being... =6.5~6.7mm, maximum thickness of leaf root Distribution location =0.35~0.45, maximum thickness in the leaf =2.7~2.9mm, maximum thickness of leaf root Distribution location =0.30~0.40, maximum thickness at the blade tip =1.7~1.8mm, maximum thickness at the blade tip Distribution location =0.2~0.40;

[0040] The trailing edge thickness of the turbine blade 2 should be as small as possible while ensuring that it is greater than the minimum processing wall thickness limit requirement. The minimum thickness should be ≥0.5mm. In this invention, the minimum trailing edge thickness of the turbine blade 2 is 0.6mm.

[0041] The beneficial effects of the present invention are as follows: The high expansion ratio high efficiency axial flow turbine of the present invention abandons the traditional long blade tie wire design, which limits the blade height, while increasing the blade root cross section to reduce root stress, significantly reducing the blade tip cross section area, and slightly reducing the middle cross section area to improve flow capacity, optimizing the wedge angle, reducing shock wave loss, and improving efficiency. It solves the technical problem that in the prior art, turbines are mostly designed with long blades, which require tie wires to ensure strength, but the tie wire structure reduces the turbine flow area, thereby reducing the turbine efficiency and increasing the assembly difficulty of the axial flow turbine.

[0042] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A high-expansion-ratio, high-efficiency axial-flow turbine, characterized in that, The turbine includes a turbine hub and turbine blades. The turbine blades are torsion blades, and there are multiple turbine blades evenly distributed along the axial centerline of the turbine hub. The inlet diameter of the turbine hub is [missing information]. The outlet diameter of the turbine hub is The axial chord length at the turbine hub is The relationship between the inlet diameter of the turbine hub, the outlet diameter of the turbine hub, and the axial chord length at the turbine hub is as follows: =0~0.364, the turbine blade inlet tip diameter is The turbine blade outlet tip diameter is The axial chord length at the tip of the turbine blade is The relationship between the turbine blade inlet tip diameter, the turbine blade outlet tip diameter, and the axial chord length at the turbine blade tip is as follows: =0~0.364; The turbine blade outlet tip diameter =170~180mm; The meridional expansion angle of the high expansion ratio high-efficiency axial flow turbine <20° <20°, and <30°; turbine blade inlet airflow angle ≤75°, the turbine blade outlet airflow angle ≤70°; turbine blade installation angle =10°~60°, leading edge wedge angle =10~21°, tail edge wedge angle =3~15°.

Images